1. Field of the Invention
The present invention relates to an organized regular micron and submicron three-dimensional microelectrode of an electrically conductive polymer having a well organized array of substantially identical formed microelectrode. More specifically, the invention concerns a electrochemically produced conductive polymer such as polyaniline or polypyrrole which is formed having a well organized micron and/or submicron array of regular microprotrusions from the surface of the polymer fabricated using a photolithographic and/or electron beam photolithographic process and the electrochemical process for the manufacture thereof.
2. Description of Related Art
Three-dimensional polymer films are particularly interesting for battery and electrochromic applications because of possible enhancement of the rate of counter-ion diffusion and migration.
Some descriptions of the preparation of polyaniline and polypyrrole polymer films have appeared in the literature. Representative examples are described below:
M. Watanabe et al. disclose in Chemical Letters, Vol. 6, pp. 1239-1242, polypyrrole/polymer electrolyte bilayer composites which are prepared by the electro-chemical polymerization of pyrrole using non-conducting polymers as a solid electrolyte.
X. Bi and Q. Pei disclose in Synthetic Metals, Vol. 22, pp. 145-156 (1987), the preparation of an electrochemical polymerization of pyrrole into a polyurethane.
M. J. Madou et al. disclose in U.S. Pat. No. 4,973,391 the preparation of electrically conducting phthalocyanine dope polymers of polyaniline which is specifically incorporated herein by reference.
Technology of the a general and specific nature is also disclosed in U.S. Serial No. 675,091, filed Mar. 25, 1991 and U.S. Ser. No. 599,002, filed Oct. 17, 1990, both of which are specifically incorporated herein by reference.
Photolithography--R. M. Penner and C. R. Martin, (1986) Journal of the Electrochemical Society, Vol. 133, No. 10, pp. 2206-2207, report a simple way of fabricating a fibrillar/microporous (i.e., microcylinder) polypyrrole membrane using a Nucleopore porous membrane that is soluble in methylene chloride. Various diameters of polymer fibrils ranging from 1000 Angstroms to 12 micrometers are possible, the resulting polymer elements are not evenly spaced (and therefore are termed an "ensemble" rather than "array") and the ensemble pattern is not reproducible.
O. M. Niwa et al. (in Kobunshi Ronbunshu, Vol. 44, No. 4, pp. 225-233 (1987)) report the fabrication of a polymer alloy film consisting of isolated arrays of polypyrrole within an insulating polymer film (e.g. polyvinylchloride) to obtain a free-standing polymer film with a high transparency and a highly anisotropic conductivity. In this approach, however, it is difficult, if not impossible, to produce a controlled, reproducible pattern (array) of polypyrrole because elements in the array tend to overgrow and spread within the insulating film during the electrochemical polymerization process.
Electron-Beam-Lithography--Electron-beam lithography systems are conventional in the art (see I. Brodie and J. Murray, (1982) The Physics of Microfabrication, Plenum Press, New York, N.Y., particularly p. 27). Electrons are used by scanning the beam to generate patterns directly from computer programs. The electron optics associated with electron-beam pattern-generation equipment are similar to those used in electron microscopy. For example, a scanning electron beam is normally used because of its ability to create high-resolution patterns (linewidth.ltoreq.5000 Angstroms), its programmability, its large depth of focus (about 10 micrometers), and its capability of providing focus and registration via a scanning electron microscope.
All references, articles, patents, patent applications, standards, reviews and the like cited in this application are incorporated by reference in their entirety.
None of these references individually or collectively disclose the present invention.
It would be very useful to have a process to produce a conductive polymeric electrode having an organized array of micron or submicron protrusions, which array is useful, for instance, electrochromic or in battery electrode applications.